When a vehicle collides with another vehicle or a building, a driver of the vehicle collides with a steering apparatus by inertia force. Conventional energy absorbing steering apparatus includes an energy absorbing apparatus for absorbing the impact energy.
In the energy absorbing steering apparatus of this kind, the steering column is movably supported relative to a vehicle body so that the steering column can move frontward relative to the vehicle when the driver of the vehicle collides with the steering apparatus. The energy absorbing steering apparatus further includes a member for absorbing the impact energy applied from the driver.
However, load applied to the steering column from the driver can be varied from different drive conditions. The load can be varied, for example, when the vehicle is driven by various drivers, because weights of the drivers are varied. Therefore, there is a danger that the energy absorption steering apparatus cannot sufficiently absorb the impact energy applied from the driver to the steering column. For overcoming the problem described above, JP2002-362381A suggests an energy absorbing apparatus in which the amount of impact energy absorbed can be controlled depending on the drive condition. In the energy absorbing steering apparatus, the amount of impact energy absorbed can be controlled by changing a rotational angle of a support pin thereby changing degree of deformation of an energy absorption plate deformed by the support pin.
However, in the steering apparatus described in the document, the rotational angle of the support pin is controlled by a motor. The motor need to have high torque so that the support pin can be removed from the energy absorption plate against counter force. Therefore, the motor tends to become larger size and cause high manufacturing cost. Further, another mechanism for regulating the rotational angle of the support pin is required. As a result, the steering apparatus tends to be still larger size.
A need thus exists for an energy absorbing steering apparatus, in which impact energy can be preferably absorbed under various drive conditions, of simple configuration. The present invention has been made in view of the above circumstances and provides such an energy absorbing steering apparatus for a vehicle.